1. Field of the Invention
This invention relates to orthotic devices, and in particular to a knee brace having a resilient, conforming interface between the brace and the users leg.
2. Description of the Prior Art
Orthotic devices generally include a substantially rigid biomechanical element that forms the basis of the skeletal support that is required for the majority of these devices, which include braces, supports and splints.
The human knee generally comprises an articulated joint between the thigh and the calf muscles that supports the weight of the human body while the person is standing, walking or running. The knee joint is primarily held together by four ligaments; namely, the anterior and posterior cruciate ligaments and the medial and lateral collateral ligaments. The knee joint can be overly weakened by injuries arising out of cartilage damage and ligament strain, which may be caused, by sports injuries, as well as from everyday exercising, or physiological problems such as osteoarthritis. Thus, the human knee is subjected to a variety of stresses and strains particularly during running and jumping movements. Athletes, in particular, are apt to incur a knee injury as a result of a blow to the knee or to a twisting of the knee, which can commonly occur in various contact sports or high stress sports, such as skiing.
There are a variety of knee braces available on the market or through healthcare providers. These range from braces that tend to totally immobilize the knee to flexible elastic bandages that are intended to provide some flexibility while eliminating lateral movement of the ligaments that support the knee. Some of these are intended to be worn as a relatively permanent device for long-term wear or braces that are intended to be worn for a short period of time during overly strenuous for a short period of time for a weakened knee. The braces have as their primary object to allow for pivoting the knee while preventing any unnatural movement, which may aggravate the knee ligaments. While the braces are intended to allow for a natural movement of the knee joint while a person undergoes walking, running, jumping, skating, various other athletic activities, they are intended also to prevent sudden movement of the upper and lower legs to one side or the other and to prevent twisting or rotation of the lower leg relative to the upper leg about the vertical axis.
Typically, the knee braces are held in place by flexible straps, which wrap about the user's thigh and calf above and below the knee, respectively. In this manner, the rigid hinge of the knee brace remains positioned on either side of the user's knee so as to mimic the hinged joint of the knee. However, it is not uncommon for the user's bodily motions to cause the flexible straps to move relative to the person's leg, thereby misaligning the knee brace with respect to the knee. This movement of the brace straps with respect to the user not only cause misalignment and therefore misapplication of the orthotic device, but also cause irritation of the user's skin by this unintended rubbing.
A problem with orthotic devices is that they must engage effectively with soft tissue in order to provide the desired support. In many parts of the body the soft tissue will move, for example by expanding or contracting as result of muscle movement. As a soft tissue changes shape, parts of the skin lose contact with the liner of the orthotic device. This reduced contact with the liner can cause the orthotic device to lose position, or move relative to the user and therefore become ineffective. The only way of overcoming this problem with existing devices is to tighten the device. This causes discomfort, prevents the skin from breathing, and can irritate the skin about the edges of the device and the liner.
The objective of any rigid knee brace is to exert a predictable force on the user's underlying skeleton. In particular, the objective is to exert a force on the tibia with respect to the femur in the user's body mass above the knee. By definition, knee braces are applied to soft tissue lying between the brace and the user's skeleton. The rigid element may include some form of liner that contacts the body of the user. The liner may have an outer fabric that is designed to contact the user's skin directly or, alternatively, to engage with clothing that a user may be wearing about the pat of the anatomy to which the orthotic device is to be attached. Soft tissue is mobile and moves in a cycle corresponding to a user's gait, whether it be through running, walking or other physical movement common to the human knee. The most mobile soft tissue is the quadriceps mechanism lying in front of the femur in the anterior thigh region. The central reference point for a knee brace is the knee joint line. In construction, an orthotic device such as a knee brace would use a joint mechanism, which mimics the movement of the joint to be supported, such as the knee, which is not just a simple hinge. Since each user's body shape is unique, the interface between the orthotic device and the user's leg cannot be predetermined in the manufacture of such a device.
What is needed then, is an orthotic device which can more readily conform to a particular user's leg, such that the straps fit snugly, yet comfortably, about the user's leg adjacent the knee, but yet provide the adequate support so as to prevent relative movement of the knee brace with respect to the knee so that the brace provides its desired function.
With a damaged knee joint, it is also not uncommon for the user to experience pain within the muscle surrounding the knee, since those muscles must now try to support the weakened knee in the absence of the normal strength provided by the now damaged ligaments. It would be advantageous if a knee brace could also provide therapeutic relief to the user's muscles while also providing the support needed for the damaged knee.
There is a need for an orthotic device, or apparatus for such a device, which will at least go some way toward overcoming disadvantages of existing constructions, or which will least provide the public with a useful alternative.